Ph.D. José Carlos Rubio has revealed his nine-year-long research into creating a light-emitting cement which could revolutionize street lighting. A researcher at Michoacan’s University of San Nicolas Hidalgo, Mexico, Rubio has been able to ‘hack’ what’s both figuratively and literally regarded as the world’s dullest building material, allowing cement to glow come nightfall by absorbing energy from the sun during the day. “Nine years ago, when I started the project, I realized there was nothing similar worldwide, and so I started to work on it… The main issue was that cement is an opaque body that doesn’t allow the pass of light to its interior,” he explained to Investigación y Desarrollo, earlier this month.
Cement is a dense, dull material and when water is added to it, small crystals are created in the resulting gel which block the light. While the exact details of Rubio’s breakthrough remain under wraps, what we do know is that the Mexican scientist found a way to modify the micro-structure of cement thus eliminating these crystals. Without these by-products, the cement becomes a pure gel which can absorb sunlight. Rubio’s development means that roads, sidewalks and even buildings constructed from this cement can emit light for 12 hours after dark.
Interestingly, most phosphorescent materials, which glow in the same way Rubio’s cement does, are made of plastic and have a short lifespan, as they eventually degrade when exposed to UV rays. These kind of materials are estimated to last up to three years before disintegrating. The hacked, glow-in-the-dark cement, however, is slated to last up to 100 years, according to Rubio. Adding to its green credentials is the fact that this cement is eco-friendly in its creation – the only byproduct of hacking cement in this way is water steam.
Currently, the glow-in-the-dark cement can be created to emit blue or green light and the light intensity can be regulated to avoid dazzling motorists, cyclists or pedestrians, or unnecessary glare. “Due to this patent, other [researches] have surfaced worldwide. In the UK, we received recognition from the Newton Fund, given by the Royal Engineering Academy of London, which chooses global success cases in technology and entrepreneurship,” explained Rubio. In 2015, global cement production reached around four billion tons, indicating a huge commercial opportunity for the scientist and his team. Meanwhile, Rubio’s continued research is currently investigating the possibility to hack other core building materials in this way, including plaster.
As cities across the world look for innovative and low-cost ways to reduce their energy consumption, a development like this is bound to attract attention from local governments and city planners. The current standard in street lights are known has high-intensity discharge lamps filled with high-pressure sodium (HPS), with cities looking to reduce their costs more recently switching to LED, which promises a 40-80% savings on energy and 50-75% on maintenance costs. However, the initial costs of LED lamps are up to four times more than traditional HPS lamps, making glow-in-the-dark cement a potential disruptor in the industry, though nothing has been revealed about its costs.